Holding jig



March 20, 1945.

- G. ST MARIE 'HOLDING JIG Filed March 2, 1944 2 Sheets-Sheet 1 Inventor Marfih 20, 1945. ca. ST. MARIE 2,371,934

HOLDING J IG Filed March 2, 1944 2 Sheets-Sheet 2 I Inventor Patented Mar. 20, 1945 2,371,934 7 HOLDING JIG George St. Marie, South Dartmouth, Mass.

Application March 2,1944, Serial No. 524,747

1 Claim.

The present invention relates to new and useful improvements in holding jigs, and has for its primary object to provide, in a manner as hereinafter set forth, novel means for firmly securing taps, reamers and other tools in position on a grinding or turning machine without the usual dogs.

Another very important object of the invention is to provide a jig of the aforementioned character which will permit the tool to be ground or turned to be readily reversed to facilitate operation on the shank thereof after the body of said tool has been treated.

Still another very important object of the invention is to provide a holding jig of the character prescribed which may be readily adjusted to accommodate different lengths of tools to be round or turned.

Other objects of the invention are to provide a holding jig of the character set forth which will be comparatively simple in construction, strong, durable, highly efficient and reliable in use, compact and which may be manufactured at low cost.

All of the foregoi11g, and-still further objects and advantages of the invention, will become apparent from a study of the following specification, taken in connection with the accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views, and wherein:

Figure 1 is a view in vertical section through a holding jig constructed in accordance with the present invention, showing the device in use.

Figure 2 is a front elevational view, showing the device mounted on the face plate of a grinding machine.

Figure 3 is a view in rear elevation of the device.

I Figure 4 is a fragmentary view in vertical section, showing a tap reversed in the jig.

Figure 5 is a view in transverse section through the device.

Figure 6 is a perspective view ofthe device, showing certain of the parts separated.

Figure 7 is a detail view in perspective of the disc which accommodates the body portion of the" chine. The plate I is further provided with a comparatively large, centrally located, circular Mounted coaxially on the plate I is a metallic sleeve 1. Adjacent the opening 5, the plate I is apertured to accommodate countersunk screws 8 which secure the sleeve I in position on said plate.

Mounted for longitudinal sliding adjustment in the sleeve 1 is a metallic bushing 9 having a 1ongitudinal groove l0 therein. The groove I0 is for the reception of a set screw II for securing the bushing 9 in adjusted position in the sleeve 1.

The outer end portion of the bushing 9 is counterbored,-as at I2, for the reception of a removable disc l3. The disc l3 has formed in its periphery a notch I for the reception of a set screw l5 for releasably securing said disc in the vided with a square, centrally located opening l6 for the reception of the usual square end portion or head ll of a tap l8 to be ground. The tap I8 is mounted between the head center 6 and the tailstock center l9lof the grinding machine.

It is thought that the operation of the device as thus far described will be readily apparent from a consideration of the foregoing. Briefly, the disc I3 is mounted in the'bushing 9 and secured by the set screw [5. The bushing 9 is mounted in the sleeve I and secured in adjusted position by the set screw II. The square end portion or head I! of the tap I8 is engaged in the opening [6 in the disc 13 and supported between the centers 6 and 19 of the machine. With the machine in operation, the set screw 15 positively secures the disc l3 to the bushing 9 for rotation therewith and the set screw ll functions in a similar manner on the bushing 9. Thus, slipping of the tap is prevented and the body 20 thereof may be ground.

To grind the shank 2| of the tap [8, said tap is reversed between the centers 6 and 19 of the machine. To accomplish this the disc I3 is removed and a disc 22 is substituted therefor. The disc 22 is provided with a centrally located opening 23 which is formed to accommodate or conform to the cross sectional shape oi? the body 20 of the tap l8. Thus, the tap l8 is'again positively secured against slipping. The disc 22 is provided with a peripheral notch 24 which receives the set screw [5.

It is believed that the many advantages of a holding jig constructed in accordance with the ing having a longitudinal groove in its periphery a set screw threadedly mounted in the sleeve and engaged in the groove for securing the bushing in adjusted position in said sleeve, said bushing having a counterbored end portion, a disc removably mounted in said counterbored end portion of the bushing, said disc having a centrally located, non-circular opening therein for the reception of a correspondingly shaped end portionof a tool to be treated, said disc further having a notch in its periphery, and a set screw threadedly mounted in the bushing and engaged in the notch for releasably securing the disc fixedly in said bushing.

GEORGE ST. MARIE. 

